A source told Look: "They have great chemistry. Sure, they've always agreed to keep things super-casual and private because of their crazy worlds, but Harry genuinely likes Cara a lot - he has done ever since they met three years ago.

"They've actually had an on/off thing going all this time when they're in the same city, but they've never had the chance to give a real relationship a shot. I can't imagine she wants to join the list of women who have been Harry'd."

They added: "Of course he might profess his love for her - and he has done that on many occasions - but she's heard it all before. He said that to her just a month before he went public with Taylor, so I imagine she's learned her lesson."